What were the starting materials of the Big Bang?

[Mitchtwitchita]

I'm in full agreement with a Big Bang start of our Universe. However, I am a little perplexed as to where these staring materials originated from. Now, I know that there is no solid answer, but I was just curious as to some theories. Thanks.

 

[bcrowell]

In the standard general-relativistic description of the Big Bang, time began after the Big Bang, and the Big Bang itself is not even a moment in time. Therefore there was no abrupt creation of any new matter.

 

[dm4b]

In the standard general-relativistic description of the Big Bang, time began after the Big Bang, and the Big Bang itself is not even a moment in time. Therefore there was no abrupt creation of any new matter.

Hi bcrowell,

Do you mean that the BB literally happened "before" t=0, or just that time, as we currently understand it, is sort of undefined before the Planck Time?

 

[zhermes]

As you supposed, there really isn't an answer, but the basic model is that there was lots of energy (at ridiculously high densities), and pair-production like processes produced quarks and electrons which then formed protons, neutrons, atoms ... etc etc. One of the biggest questions is why was more matter produced than anti-matter.

You can then, of course, ask where did that energy come from... and i think that is what BCRowell might be getting at---at some point, there isn't a 'before'... i.e. there was no 'time' at which the energy came into being, or a condition before that state.

You might want to look into eternal inflation models which might be a little more satisfying.

 

[marcus]

General discussion of this question at the AEI (Albert Einstein Institute) pubic outreach website:
http://www.einstein-online.info/spotlights/cosmology/?set_language=en
Specifically the essay "A Tale of Two Big Bangs"
http://www.einstein-online.info/spotlights/big_bangs

Big bang can either mean "t=0" or the whole process that came after that (with some ambiguity about whether you include inflation.)

Here "t=0" is just a short way of saying where the standard vintage-1915 GR theory breaks down. The general consensus is that the breakdown or "singularity" indicates that GR needs to be fixed---replaced by a more robust quantized theory that contains the classical results (about later times) but does not break down.

The Einstein-Online "2BB" essay is just a page long and explains this pretty well.
The research area where people are most actively working on a more rugged replacement version of cosmology is called "Quantum Cosmology".

Here is a link to the QC papers that have appeared since 2009
http://www-library.desy.de/cgi-bin/spiface/find/hep/www?rawcmd=FIND+DK+QUANTUM+COSMOLOGY+AND+DATE+%3E+2008&FORMAT=www&SEQUENCE=citecount%28d%29
There are now 227 QC research papers this search comes up with. They are ranked by the number of times each paper has been cited by other papers so that generally speaking you get the most significant papers first---those most characteristic of current work and thinking in the field.

 

[dm4b]

When did matter (i.e. anything with rest mass) first come into being? At t=0? Or, at some later time t=x? What is x?

I'm just thinking of Roger Penrose's CCC model. He has the current cycle, or aeon, ending when all the matter is gone from the Universe. We'll ignore his rogue electron problem for now, as he seems to be doing too. Anyhow, no matter = no clocks, no space = new Big Bang.

But, if matter did not exist right from the get go at t=0, how did the current cycle ever get started and reach the point it is at now?

Is this a flaw in RP's theory, or my own line of thinking? Wait, I think I can guess the answer ;-)

 

[marcus]

I won't venture to explain Penrose CCC, which as you point out still has several missing pieces to fill in. However I did find this April 2011 video lecture of him discussing it quite helpful.
http://pirsa.org/11040063/
He had already lectured about CCC to the Perimeter audience, so they were familiar with it. And since the talk was just this year, he had a chance to address the criticisms that have been made. Plus he could report on the current status and what problems need to be addressed. I don't know if the CCC idea is ultimately a good one, but this video talk is quite good, I thought.

 

[dm4b]

I won't venture to explain Penrose CCC, which as you point out still has several missing pieces to fill in. However I did find this April 2011 video lecture of him discussing it quite helpful.
http://pirsa.org/11040063/
He had already lectured about CCC to the Perimeter audience, so they were familiar with it. And since the talk was just this year, he had a chance to address the criticisms that have been made. Plus he could report on the current status and what problems need to be addressed. I don't know if the CCC idea is ultimately a good one, but this video talk is quite good, I thought.

Hi marcus,

yes, I saw your other post on that video and I'm about half way through it - maybe he'll address my question during the 2nd half. Good video.

Thanks for the above links too. That Einstein-Online-Info site is pretty cool.

 

[bcrowell]

When did matter (i.e. anything with rest mass) first come into being? At t=0? Or, at some later time t=x? What is x?

In standard GR there is no t=0. Matter exists at all t>0. Time only exists for t>0. Matter exists at all times.

 

[dm4b]

In standard GR there is no t=0. Matter exists at all t>0. Time only exists for t>0. Matter exists at all times.

Isn't t=0 the singularity?

In what form did matter exist? I'm guessing the fundamental particles such as electrons, and maybe quarks. It would seem they would have had to anyhow, for CCC to be consistent.

 

[bcrowell]

Isn't t=0 the singularity?

Yes. In standard GR, the singularity isn't a point in spacetime, so t=0 is not a point in time.

In what form did matter exist? I'm guessing the fundamental particles such as electrons, and maybe quarks.

We don't have any theory of particle physics in which matter is made out of anything other than fundamental particles. On the other hand, it's conceivable that there were exotic processes going on like black holes being created in the collision of gravitational waves. Beyond a certain energy scale, we just don't know for sure how matter works.

It would seem they would have had to anyhow, for CCC to be consistent.

CCC isn't standard GR. I was only trying to lay out the description in standard GR.

 

[dm4b]

We don't have any theory of particle physics in which matter is made out of anything other than fundamental particles. On the other hand, it's conceivable that there were exotic processes going on like black holes being created in the collision of gravitational waves. Beyond a certain energy scale, we just don't know for sure how matter works.

Understood. Penrose (in the video Marcus put up) talks about the rogue electrons potentially evaporating.

I just always assumed being fundamental, or as you implied, not being made of other, smaller constituents, they would have had to be their from the "beginning", CCC being correct, or not.

However, the fact that he brings up "electron evaporation" makes me wonder about that idea now.

 

[bcrowell]

Understood. Penrose (in the video Marcus put up) talks about the rogue electrons potentially evaporating.

I think that video might be out of date. I believe Penrose has given up on the exotic particle physics predictions of CCC, because they just can't be reconciled with observation.

I just always assumed being fundamental, or as you implied, not being made of other, smaller constituents, they would have had to be their from the "beginning", CCC being correct, or not.

However, the fact that he brings up "electron evaporation" makes me wonder about that idea now.

Particles are created and destroyed all the time. For instance, electron-positron pairs are created by cosmic rays when they hit the atmosphere.

 

[marcus]

I think that video might be out of date. I believe Penrose has given up on the exotic particle physics predictions of CCC, because they just can't be reconciled with observation..

The video of Penrose's talk was recorded less than 20 days ago, on 6 April, when he gave the talk, so his views (whatever they are) probably haven't changed much. It's a pretty lively presentation, I'd recommend it for anybody who has a free hour and is curious about the current status of CCC.
http://pirsa.org/11040063/
But I don't subscribe to CCC myself.

 

[dm4b]

Particles are created and destroyed all the time. For instance, electron-positron pairs are created by cosmic rays when they hit the atmosphere.

Most definitely, but it sounds like he is talking about something different here. It sounds like it is literally an evaporation of mass.

I still need to watch the 2nd half though.

maybe somebody else can provide clearer details on the whole rogue electron problem.

 

[bcrowell]

Can anyone provide a specific time-mark in the video where he talks about the particle-physics stuff? Even better would be a paper rather than a video :-)